The present invention relates to a valve arrangement for providing clinical nutrition, a flow set comprising the valve arrangement, a method for producing the valve arrangement, use of the valve arrangement in providing nutrition, and methods of treating patients by administering an effective amount of a liquid composition through the valve arrangement.
Hospital patients are routinely provided fluids for maintaining a good state of hydration. Furthermore, fluid can act as a carrier for nutrients in order to provide a patient with adequate nutrition, for example, following surgery.
Systems for the administration of fluids to a patient are widely known. The manner of propelling the fluid to a patient may be by gravitation; by means of pressure applied on a deformable container; or by means of a pump. In pump-operated administration systems, the pump must be capable of administering the fluid in a controlled, generally continuous manner.
Pumps are employed to meet the need for a high degree of accuracy in the administration of fluids, to protect the patient and to maximize the effectiveness of medication.
An example of a pump that is presently used for pumping fluid through a tube to a patient is a rotary peristaltic pump. This type of pump suffers from the disadvantage that if the flow set, the tubing through which the fluid is pumped, is not connected properly or is disconnected from the pump, a free-flow condition can occur. Furthermore, in general, this type of pump does not have antifree-flow protection. Uninhibited free flow of fluid to a patient can be dangerous for the patient, e.g., it can lead to drowning.
Another example of a pump presently used to administer fluid to a patient is a linear peristaltic pump. This type of pump suffers from the problem that if the flow set is not connected properly, it is subject to a (pumped) back flow of liquid in a direction opposite to the intended direction of flow to a patient. It is clear that if a free flow or back flow of fluid proceeds unchecked, it can be dangerous for a patient.
To cope with the problem of free flow, a piece of apparatus known as an occluder has been used. The occluder operates by folding a length of resilient tubing, thereby pinching the tubing and causing its internal diameter to be reduced, thereby inhibiting flow therethrough. This arrangement works, but it has been found that it suffers from the problems that if an elastic part of the occluder (for keeping a resilient tube folded) is over stretched, it can be broken easily. Therefore, if an operator disconnects the pump, but fails to close the tubing, for example with a roller clamp, a free flow condition may occur.
Therefore, a need exists for an apparatus which permits a good flow of fluid to a patient, but which addresses the problems presented by uninhibited free flow and flow back.